[swift_snapshot_tool] Make the required platform macOS v14 so that we can use some newer APIs.

Author: gottesmm

utils/swift_snapshot_tool/Package.swift

@@ -5,7 +5,7 @@ import PackageDescription
 
 let package = Package(
   name: "swift_snapshot_tool",
-  platforms: [.macOS(.v12)],
+  platforms: [.macOS(.v14)],
   products: [
     // Products define the executables and libraries a package produces, making them visible to other packages.
     .executable(